#define _CRT_SECURE_NO_WARNINGS 1
int kthToLast(struct ListNode* head, int k)
{
    struct ListNode* n = head;
    struct ListNode* p = head;
    while (k--)
    {
        n = n->next;
    }
    while (n)
    {
        n = n->next;
        p = p->next;
    }
    return p->val;
}